The present invention relates to a metal cutting insert for profile turning and grooving. Such inserts are known which comprise longitudinally extending top and bottom surfaces, a forward end of the insert being provided with a cutting edge of circular shape which intersects rearwardly extending side edges of the insert. The top surface is provided with a chip forming surface located radially inside the cutting edge. The insert cuts a workpiece as the latter rotates about an axis, and the insert is displaced in a direction parallel to that axis.
There occurs a problem when using such rounded inserts for longitudinal turning, because chips of varying thickness are obtained along the cutting depth. At the radially innermost point (i.e., radially with respect to the axis of rotation of the workpiece), where the chip thickness is smallest, it is desirable to have a rear chip breaking wall so designed that a more favorable chip formation is achieved. On the other hand, the chip breaking wall should be different to achieve optimum breaking of thicker chips occurring at the outer periphery of the workpiece.
One object of the present invention is to provide an insert which performs plurality of turning and grooving operations while maintaining good chip control regardless of the chip thickness.